Class Reptilia: General Characteristics, Examples, and NEET Biology Notes
Definition
- Word Reptiles has been taken from Latin word Repes that means creeping or crawling.
- Reptiles are class of vertebrates that are cold blooded and skin is covered by scales and their young one are hatched from their egg.
General Characters
- They do locomotion through creeping or crawling.
- They are mostly terrestrial but some are also found in water
- Their skin is dry and cornified and covered by epidermal scales or scutes.
- They do not have external ear opening and A tympanum represent the ear.
- They have two pairs of limb if present.
- Reptiles are Poikilothermal or cold blooded.
- Heart is three chambered except the Crocodiles have four chambered heart. ❤️
- Snake and Lizard shed their scale as skin cast.
- Saxes are seprate. Fertilization is internal.
- They are oviparous and development is direct.
Video Guide: Key Topics & Timestamps
Watch the detailed explanation on our YouTube channel "Grip the Biology":
- 00:00 - Introduction to Class Reptilia
- 00:48 - Etymology: Why they are called "Reptiles"?
- 02:03 - Body Surface: Dry & Cornified Skin (Scales)
- 03:15 - Habitat and Poikilothermic nature
- 04:33 - Heart Structure and The Crocodile Exception
- 05:55 - Reproduction and Development in Reptiles
- 07:07 - Classification and Important Examples
- 08:42 - Non-poisonous vs Poisonous Snakes
- 10:38 - Anatomy: Scales and Scutes Explained
*Click on the time to watch that specific part on YouTube.
Examples of Reptiles
Chelone
- It is commonly called as Turtle.
- Body is covered by a outer hard shell made up of Keratin. Upper part of shell is called carapace and lower part of shell is plastron.
- They have paddle like flippers on fore limbs.
- They have four limb with five digits hence called Penta dactyle.
- They are tooth less and omnivorous reptile.
- They have trochlear system on jaw adductor muscle.
💡 NEET KEY POINTS
📝 Monocondylic skull: Skull has one condyle in which vertebral column is fit.
📝 Tympanum : It present the internal ear.
📝 Nitrogenous waste : It is Uricotelic.
- They use their shell to store lactic acid and to buffer the acidity.
- They are oviparous with internal fertilisation.
- They are uricotelic due to release of uric acid as excretory waste.
- They have no external ear and their skull is Monocondylic .
- skull. Some species of chelone are are endangered.
 |
| Chelone ( Turtle) |
Python
- It is commonly called as Ajgar.
- It is large , non poisonous snake with triangular head with sharp teeth and prehensile tail.
- Head has heat sensitive pits on their snouts and vertical pupils.
- Skin is flexible with smooth scales.
- They have a primitive lungs with reptiles ancestor characters.
- They are strike predator and kill the prey through its construction.
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| Python ( Ajgar) |
- Female Python lay leathery eggs and coiled around them to keep their warm.
- Python can live more than 20 years.
- Python secrete large amount of mucus with trace amount of venom during the swallowing of prey.
Reptiles characters At a Glance
| Feature | Description |
|---|---|
| Body Surface | Dry and cornified skin; epidermal scales or scutes. |
| External Ear | Absent; represented by tympanum. |
| Heart | Usually 3-chambered (except Crocodiles, which are 4-chambered). |
| Temperature | Poikilotherms (Cold-blooded). |
| Respiration | Always through lungs. |
| Fertilization | Internal; usually oviparous with direct development. |
Testudo
- It is commonly called as Tortoise.
- It has dome and oval shape shell with horny scales.
 |
| Testudo ( Tortoise ) |
- When, it withdraw it's head into shell than it neck look like S shape.
- Carapace is convex with no nuchal plate whereas plastron in Concave.
- There are large yellow stars on both marginal and central scales.
- Feet are for walking on land. Phalanges are reduced into two in each digit.
- Testudo can live upto 200 or more years. It can hibernate in cold water.
- It is diurnal, herbivores but it can feed insect and worms.
Hemidactylus
- It is commonly called as Wall lizard.
- Body is covered by scaly integuments. Scales are minute and smooth .
- Head is broad and flat. Eyelids are fused over the eyes. Ear opening is vertical.
- Tongue is short, sticky and protrusible.
- Digits are clawed and dilated with row of ridged lamellae on lower surface for movement of ceiling or smooth surface.
Hemidactylus ( Wall lizard )
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- Tail is long and can break off at any un ossified part of caudal vertebrae. This is called Autotomy.
- Tail has great power of regeneration. Supra temporal arch is present.
- Parietal organs are present. Vertebrae are amphicoelous.
- They are oviparous and lay eggs.
Calotes
- It is commonly called as Garden lizard and found in open field or hedge.
- Body is covered by imbricate epidermal horny scales. are minute and smooth .
- A crest of sharp spines is present on dorsal surface of neck and back.
- Body is divided into head, trunk and tail. Mouth is anteriorly located on head.
- Cloacal aperture is located at ventral surface of root of tail.
- Tail is long and cylindrical and does not has power of regeneration.
 |
| Calotes ( Garden lizard) |
- It has capability to change the body color with respect to surrounding , called camouflage.
- There are 9 or 10 pairs of upper and lower labials.
Alligator 🐊
- Body is covered by epidermal horny scales.
- Head is short and broad. Snout is also broad and rounded.
- Limbs are Pentadactyle with five finger and four toes. Fingers and toes are webbed.
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| Alligator |
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- Tail is laterally compressed.
- Mandibular symphysis is short and extended upto level of fourth and fifth tooth.
- There are 17 to 20 teeth in upper jaws and 18 to 20 teeth in lower jaws.
- Dorsal shield is formed by the 6 to 8 longitudinal series of Bony scutes.
- The neck is protected by the two pairs of large scutes.
Crocodilus
- It is commonly called as Crocodile.
- Head is triangular and rough at the top. Snout is short rathar than broad.
- Limbs are Pentadactyle with five finger and four toes. Fingers and toes are webbed.
- Tail is long and laterally compressed.
- Mandibular symphysis is short and extended upto level of fourth and fifth tooth.
 |
| Crocodilus |
- There are 19 teeth in upper jaws and lower jaws.
- The nuchal scutes are six in number.
- Dorsal shield is formed by the four to six row of larger scutes. Out of these, central one is broader.
Bungarus
- It is commonly called as Krait
- Body is elongated and slender. The color of body is steel blue with cross bars or white speck on dorsal side and white in under side.
- Head is with normal shield and not differentiated from neck .
- Loreal is absent. Two post ocular and one pre ocular are present.
- Seven supra labial are present . Third and fourth supra labial touches with eyes.
- It is nocturnal and carnivorous and feeds of rats and Lizards.
- Bungarus is poisonous and it's venom is neurotoxic.
 |
| Bungarus ( Krait ) |
- Bungarus is oviparous.
Vipera
- It is commonly called as Russell viper or Dabois.
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| Vipera |
- Body is elongated and slender. The color of body is pale brown with three longitudinal series of black spots on dorsal side and yellowish white in under side.
- Head is triangular and covered with small imbricate scale on upper surface.
- The eye 👀 are with golden iris and with elliptical pupils.
- Ten to thirteen supra labial are present . Fourth supra labial is largest and does not touch with eyes.
- It is nocturnal and carnivorous and feeds of rats and Lizards.
- Viper is poisonous and it's venom is Haemotoxic. Viper is Viviparous.
Naja
- It is commonly called as Ki ng Cobra.
- Neck is dilatable and cervical ribs are elongated. The expansion of neck and cervical ribs forms hood.
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| Naja ( Cobra ) |
- Head is with normal shield and not differentiated from neck .
- The upper part of hood has a Binocoellate mark. This mark is called as spectacles.
- Third supra labial is large and touches with eyes and nasal.
- It is nocturnal and carnivorous and feeds of rats and Lizards.
- Cobra is poisonous and it's venom is neurotoxic.
- Eyes are very small with rounded pupils. Loreal is absent. Frontal shield is truncated.
- Three post ocular scales are present.
Examples table Reptiles for NEET
| Common Name | Scientific Name | Category |
|---|---|---|
| Turtle | Chelone | Reptile |
| Tortoise | Testudo | Reptile |
| Tree Lizard | Chameleon | Reptile |
| Garden Lizard | Calotes | Reptile |
| Cobra | Naja | Poisonous Snake |
| Krait | Bungarus | Poisonous Snake |
| Viper | Vipera | Poisonous Snake |
Chameleon
- It is commonly called as tree lizard.
- It has long sticky tongue used to catch the prey.
- It has movable eye which can move independently at 360 degree.
 |
| Chameleon ( Tree lizard) |
- Chameleon has color cells on skin called chromatophore to change the color.
- Toes are modified as such way that these can grasp the things.
- It has ability to change color for camouflage, communication and temprature regulation.
- The tail is prehensile to grasp the things.
- Generally they are oviparous but some give birth to young one.
🎯 NEET MULTIPLE CHOICE QUESTIONS
🔥 100% CHALLENGE
"Questions yahi se aayega... taiyari jeet ki!"
1. Which of the following statement is correct for Reptiles.
A. Tail is completely absent in all members.
B. Tympanum represent the External ear.
C. They can live in terrestrial habitat.
D. They follow creeping and crawling mode of locomotion.
Answer: D
2. Consider the following features of skin of Reptiles and select the correct code
1. Epidermal scale
2. Epidermal scutes
3. Dry skin
4. Cornified skin
A. 1 and 4 B. 2 and 3
C. 1, 2 and 3. D. 1, 2,3 and 4
Answer: D
3. Given below are two statements and select the correct option
Statement I : Reptiles do not have external ear.
Statement Il : Tympanum represent internal ear.
A. Statement l is true and statement ll is false.
B. Statement l is false and statement ll is true.
C. Both statement I and II is true.
D. Both statement I and II is false.
Answer: C
4. Reptiles have three chambered heart except
A. Crocodile B. Snake
C. Lizard D. Turtle
Answer: A
5. Consider the following statement and select the correct code
1. Reptiles are Poiklothermal because they can change their body temperature with the ambient temperature.
2. All members have two pairs of limbs.
A. Only 1
B. Only 2
C. Both 1 and 2
D. Neither 1 nor 2
Answer:A
6. Which one of the following Reptiles shed their scale as skin cast.
A. Turtle and Tortoise
B. Crocodile and Lizard
C. Lizard and Snake
D. Snake and Turtle
Answer: C
7. Match the list
A. Chelone 1.Turtle
B. Testudo 2. Tortoise
C.Alligator 3. Alligator
D.Crocodilus 4.Crocodile
A B C D
A. 1 2 3 4
B. 1 3 2 4
C. 4 1 3 2
D. 4 3 1 2
Answer : A
8. Which of the following statement is correct for Reptiles.
A. Saxes are separated.
A. Saxes are separated.
B. Crocodile has three chambers heart.
C.Chelone shed their scale as skin cast.
D. Tympanum is absent in Snakes.
Answer: A
9. Match the list
A. Development 1. Direct
B. Fertilization 2. Indirect
C.Reproduction 3. External
4.Internal
5. Oviparous
6. Viviparous
A B C
A. 1 3 5
B. 1 2 5
C. 2 4 6
D. 2 3 6
Answer : B
10. Match the list
A. Chameleon 1.Wall lizard
B. Hemidactylus 2. Tree lizard
C. Calotes 3. Garden Lizard
A B C
A. 1 3 2
B. 1 2 3
C. 2 1 3
D. 2 3 1
Answer : B
11. Which of the following is not a poisonous snake.
A.Python B. Naja
C. Viper D. Krait
Answer : A
12. Match the list
A. Naja 1. Krait
B. Vipera 2. Ajgar
C. Bungarus 3. Viper
D. Python 4. Cobra
A B C D
A. 1 2 3 4
B. 1 3 2 4
C. 4 1 3 2
D. 4 3 1 2
Answer : D
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